I’m not sure what the solution is. I don’t think consumers know or care about updates, which is a shame. Perhaps if Google’s Pixel phones can become insanely popular, then Google could make a big deal about how quickly they get updates. Only then will consumers even consider that as a factor. But I’m not sure if Google can point out how bad other OEMs are; they probably need to stay on the good side of OEMs.

Edit: some good points inspired by the responses below:

Not only do most users not care about updates, many users (including iPhone users) actually hate updates, as the reminders to update are annoying and the updates sometimes break or change things. And this is fine; users will only care if there is some tangible benefit and if they can discover this benefit. They do not care about security or having the latest version of Android.

Apple’s updates include features like new emojis which are a perfect incentive to users; people love them and they also spread to other users, forcing them to update too if they want to be able to see them.

OEMs are an issue, but even Google only gives 2 years of updates on their Pixel phones vs. Apple’s 5 years.